Sun as the Lord of Simha or Leo
If your Lagna is Simha(Leo) your lagna Lord is Sun(Surya). The 5th house Lord and 8th house Lord is Jupiter. Though the 8th is very malefic according to Vedic scriptures the deep friendship of Jupiter with the Lagna Lord and being the Lord of 5th house which is Trikona Jupiter gives good results for this ascendants. Jupiter is considered auspicious. Mars or Kuja who is the Lord of 4th and 9th house a Kendra and a Trikona, and being a great friend to Sun or Surya is highly benefic for this lagna. Mercury who is neutral to Sun is considered malefic for the reason that he is the Lord of 2nd and 11th houses. But some astrologers consider this as neutral Planet for Simha Lagna. Though Venus who is the Lord of 3rd house and 10th house, one being malefic and the other being a Kendra is still considered bad owing to its enmity to Surya or Sun. Chandra or the Moon on the other hand though it is the lord of 12th house is reckoned as benefic owing to its friendship with Surya. Now the Saturn, who according to Hindu Mythology is the Son of Surya. However owing to his enmity towards his father and also due to Lord of 6th and 7th houses of which one is a malefic house and other neutral he is very malefic for this Lagna. Rahu and Ketu are both are inimical to Sun and hence they are malefic for this Lagna.
Mercury as the Lord of Kanya (Virgo)
If your Lagna or ascendant is in Kanya or Virgo then the Lord of Kanya or Virgo is Mercury (Budha). Mercury is a mild planet and acquires the property of the Planet with which he associates. Generally a Subha Graha but can give the results with which it generally associates with. The 5th and 6th houses from this Lagna are owned by Saturn or Shani. Hence Saturn can be said to be the friend to this Lagna Lord hence auspicious. The Venus or Shukra is the lord of 2nd and 9th house hence auspicious for this Lagna. Kuja or Mars who is the owner of 3rd and 8th houses, and being inimical to the Lagna Lord Mercury(Budha) is a malefic Planet for this lagna. The Planet Jupiter is mythologically inimical to the mercury or Budha. Hence though He is the Lord of fourth and seventh house he is slightly inauspicious for this Lagna.Though Sun or Surya is the neutral planet being the ruler of house 12th in this case he is slightly inauspicious for this Lagna. Chandra or Moon being the ruler of house 11 in this case is neutral. Rahu is equivalent to Saturn and is auspicious in this case and Ketu being the equivalent to Mars is inauspicious in this case.